Progress in analgesia for labor: focus on neuraxial blocks.

Neuraxial analgesia is widely accepted as the most effective and the least depressant method of providing pain relief in labor. Over the last several decades neuraxial labor analgesia techniques and medications have progressed to the point now where they provide high quality pain relief with minimal side effects to both the mother and the fetus while maximizing the maternal autonomy possible for the parturient receiving neuraxial analgesia. The introduction of the combined spinal epidural technique for labor has allowed for the rapid onset of analgesia with minimal motor blockade, therefore allowing the comfortable parturient to ambulate. Patient-controlled epidural analgesia techniques have evolved to allow for more flexible analgesia that is tailored to the individual needs of the parturient and effective throughout the different phases of labor. Computer integrated systems have been studied to provide seamless analgesia from induction of neuraxial block to delivery. New adjuvant drugs that improve the effectiveness of neuraxial labor analgesia while decreasing the side effects that may occur due to high dose of a single drug are likely to be added to future labor analgesia practice. Bupivacaine still remains a popular choice of local anesthetic for labor analgesia. New local anesthetics with less cardiotoxicity have been introduced, but their cost effectiveness in the current labor analgesia practice has been questioned.